Rotary engine with epicyclic rotor



May 26, 1970 M. s. RASHEV ROTARY ENGINE WITH EPICYCLIC ROTOR 7Sheets-Sheet 1 Filed March 13, 1968 11w ENTOR. 3| Stoyomov RASHEV Mabelhis AfloI-ne May 26, 1970 M. s. RASHEV ROTARY ENGINE WITH EPICYCLICROTOR 7 Sheets-Sheet 2 Filed March 13, 1968 INVENTOR. Mihail SFoyanovRASHEY BY:

his Aflorn q May 26, 1970 M. S. RASHEV ROTARY ENGINE WITH EPICYCLICROTOR Filed March 13, 1968 k :fi

M r: M

M l 1 a l I l :====4 IM ENTOR: M I Miholilsfqfanov BY:

, J MQQW his Affgrney y 6, 1970 M. s. RASHEV 3,514,236

ROTARY ENGINE WITH EPICYCLIC ROTOR Filed March 15, 1968 '7 Sheets-Sheet4 Buihqil .SToyanoV RASHEV m 0. Mew

his Affornty May 26, 1970 M. s. RASHEV 3,514,236

ROTARY ENGINE WITH EPICYCLIG ROTOR Filed March 15, 1968 7 SheetsSheet 51N1 "ENTORT Mlha'll Sioyanov RASHEV B his Afforney 6, 1970 M. s. RASHEV3,514,236

ROTARY ENGINE WITH EPICYCLIC ROTOR Filed March 13, 1968 7 Sheets-Sheet eLVIICNIOR. Mihail Sioyanov RASHEV m.-

his Afforney May 26, 1970 M. s. RASHEV 3,514,236

ROTARY ENGINE WITH EPICYCLIC ROTOR Filed March 13, 1968 7 Sheets-Sheet'7 will,

INVEN'IUR? Mihail sToyomov RASHEV BY: t z his Afiorney United StatesPatent O Int. Cl. F02b 55/08, 55/06, 55/16 U.S. Cl. 418144 9 ClaimsABSTRACT OF THE DISCLOSURE An improved rotary engine is provided withthree combustion chambers each having a variable volume and relativelyfixed angular bondaries defined by adjacent pairs of inwardly directedcusps spaced at 120 around the periphery of the engine stator. Thestator is drivingly coupled to the engine rotor in such a manner thatthe rotation of the rotor causes the cusps to oscillate over spacedportions of an epicyclic path identical to that defined by an epicyclicouter surface of the rotor, thereby maintaining the rotor surface inengagement with each of the three cusps at all times.

BACKGROUND OF THE INVENTION Several types of rotary internal combustionengines employ lobed pistons which respectively contact selectedportions of a surrounding shaped stator through suitable seals to definecombustion chambers, which are provided with suitable ignition means.Each chamber is supplied at appropriate intervals with an ignitablemixture. After ignition has taken place in one chamber the piston isdriven away from its then-defined place of engagement with the statorperiphery, and its lobed portion contacts a different predeterminedplace on the stator periphery to define the boundary of a new workingspace for the next portion of the cycle. Thus, as the piston goesthrough its revolution the position of the operative combustion chambervaries. Each point on the stator engageable with a piston lobe to form achamber boundary is subjected to a cyclical impact load as the chamberboundary associated with that point is established during the pistonrevolution. Such repeated impact loads fatigue the engine elements andthe seals and cause premature failure.

SUMMARY OF THE INVENTION This drawback is avoided by the improved rotaryengine of the present invention, wherein the stator is provided withthree combustion chambers of varying volume but relatively fixed angularposition. The chambers are peripherally bounded by successive pairs ofthree inwardly extending cusps disposed on the stator periphery andspaced at 120 angular intervals about the rotor axis, which is fixedwith respect to the surrounding stator. The stator is drivingly coupledto the rotor in such a way that upon the rotation of the rotor the threefixed cusps on the stator oscillate back and forth over spaced portionsof a common epicyclic path relative to the rotor axis. The rotor isprovided with an outer epicyclic surface coincident with the path ofoscillation of the cusps so that the moving rotor is always in contactwith the stator at the three oscillating points defining the boundariesof the combustion chambers. With this arrangement, the seal at eachjunction between cusps and the epicyclic rotor surface is subjected tocontrolled steady pressure rather than to intermittent impact loads sothat the problem of fatigue is eliminated to a large degree.

In an illustrative embodiment of the invention, the

"ice

rotor is aflixed to a hollow engine shaft which rigidly carries a firstgear coaxially therewith in spaced relation to the rotor. Threerotatable non-orbiting planetary gears engage the outer periphery of thefirst gear at 120 intervals about the rotor axis. Three statorprojections extending from the respective cusps are eccentricallycarried within the planetary gears to oscillate the cusps epicyclicallywith respect to the rotor axis as the rotor rotates. Each chamber has aspark plug extending through the peripheral wall of the statorintermediate the bounding cusps. Four-cycle operation of each chamher isaccomplished by providing the rotor with spaced radial intake andexhaust channels communicating with a carburetor and the outside air,respectively, through the hollow engine shaft.

The driving coupling between the rotor and the stator is operativeoutside the combustion region of the engine so that vibration, weightand cooling requirements of the engine are minimized. The rotor andstator are finned and are air-cooled by suitable means carried on theengine shaft.

BRIEF DESCRIPTION OF THE DRAWING The nature of the invention and itsadvantages will appear more fully from the following detaileddescription taken in connection with the appended drawing, in which:

FIG. 1-4 are simplified end views of the combustion chambers disposed ina rotary engine constructed in accordance with the invention, depictingthe relative volumes of the chambers at successive portions of the rotorcycle;

FIG. 5 is an end view, partially broken away, of a rotary engineembodying the combustion chambers shown in FIGS. l-4;

FIG. 6 is a longitudinal view, partly broken away, of the engine of FIG.5, illustrating the rotor-stator coupling and the engine lubricatingsystem;

FIG. 7 is a longitudinal view, partly broken away, of the engine of FIG.5, illustrating the components mounted on the engine shaft and theengine air-cooling system;

FIG. 8 is a perspective view of the sealing arrangement for the engineof FIG. 5;

FIG. 9 is a fragmentary view of a portion of the stator wall of theengine of FIG. 5, illustrating alternative forms of several of thepackings supported therein;

FIG. 10 is a sectional view taken on line 10-10 of FIG. 9;

FIG. 11 is a sectional view taken on line 11--11 of FIG. 9;

FIG. 12 is a fragmentary view of the sealing arrangement of FIG. 8,illustrating details of a corner packing and its means of retention;

FIG. 13 is an enlarged fragmentary view of a portion of the arrangementof FIG. 12; and

FIG. 14 is a fragmentary longitudinal view of the shaftmountedcomponents of an engine similar to that of FIG. 5, illustrating fuelinjection passages in the rotor.

DETAILED DESCRIPTION Referring now in more detail to the drawing, FIG. 1illustrates a combustion portion 69 of an illustrative rotary engine,constructed in accordance with the invention. The portion 69 includes anessentially annular stator wall 32 supported as described below around afixed engine axis 70. The axis 70 extends in the direction perpendicularto the figure. An inner periphery 32a of the stator wall includes threeessentially identical arcuate portions bounded by three inwardlyextending cusps a, 75b, and 75c. The cusps 75 are respectively disposedat angular intervals around the stator wall 32 with reference to thefixed engine axis 70. Each of the cusps 75 carries a suitable packing(not shown) for forming a fluid-tight seal with a rotor 10, as describedbelow.

Disposed behind the stator wall 32 and represented 'by dotted lines inthe figure is a planetary gear arrangement consisting of a central gear6 mounted coaxially with the engine axis 70 and three non-orbitingplanetary gears 21 externally engaging the the periphery of the gear 6at 120 angular intervals around the engine axis 70. The planetary gears21, each of which is associated with a separate one of the cusps 75, aremounted for rotation about individual fixed axes 74 respectivelyparallel to the engine axis 70.

The stator is eccentrically supported for oscillation about the engineaxis 70 by three projections 2323 extending from each cusp 75perpendicular to and inwardly of the plane of the drawing and rigidlyreceived in a separate one of the planetary gears 21 at an off-axislocation spaced a predetermined distance A from the axis 74 of theplanetary gear. With this arrangement, the rotation of the planetarygears 21 in the counter-clockwise direction about their fixed axes 74(as a result, e.g. of the clockwise rotation of the central gear 6 aboutthe engine axis 70) will cause each of the projections 23 to rotateabout the associated planetary gear axis 74. Since each gear 21 isconstrained against orbital motion around the periphery of the gear 6,each projection 23 will drive the associated cusp 75 joined thereto inan oscillatory path about, rather than a rotational path about, ratherthan a rotational path around the engine axis 70. Each cycle of rotationof a plantary gear 21 causes a corresponding cycle of oscillation of theassociated cusp 75. Since every off-axis point on the gear 21, includingthe point of contact with the projection 23, will describe anepicyclical path as it rotates about its fixed axis on the periphery ofthe gear 6, the associated cusp 75 will likewise describe an epicyclicalpath as it oscillates. The relative angular positions of each of theprojections 23 on the radius A of the planetary gears are chosen so thatthe oscillations of all of the cusps 75a, 75b, and 750 are in phase,i.e. so that the entire stator 32 is oscillated through a total angularsector a about the axis 70 along the common epicyclic path in anonbinding manner once during each cycle of rotation of the nonorbitingplanetary gears 21. The resulting oscillation of the stator is shown inFIGS. 1-4 with particular reference to the position of the cusp 750.Thus in FIG. 1, which for present purposes can be taken to be the startof a cycle of oscillation of the associated planetary gear 21, theprojection 23 on the gear 21 is initially directly below the axis ofsuch gear, and the cusp 75c is in alignment with a reference verticalaxis 110. In FIG. 2, the gear 21 has rotated through a quarter of arevolution to one of its maximum displacement positions, and theprojection 23 has correspondingly moved the stator counterclockwise fromthe axis 110 through the angular sector a/Z with respect to the engineaxis 70. In FIG. 3, the gear 21 has rotated another quarter of arevolution and the stator has moved back clockwise through the angularsector oz/Z to its initial position. In FIG. 4, the gear 21 has rotatedthrough another quarter of a revolution to its opposite maximumdisplacement position, and the stator has moved clockwise from the axis110 through an angular sector 06/2 with respect to the engine axis 70.It will be evident that, during the final quarter of revolution of thegear 21, the stator will move back counterclockwise through the angularsector a/2 to its initial position shown in FIG. 1 to complete its cycleof oscillation. It is seen, therefore that the stator has a zero netangular displacement during each cycle of rotation of the gear 21.

The rotor 10 is disposed within the stator and, like gear 6, is mountedcoaxial with the engine axis 70. The rotor 10 is provided with anepicyclical outer surface 76 that is coincident with the epicyclicalpath traversed by the periphery 32a of the stator during each cycle ofoscillation thereof. Thus, as the rotor 10 revolves about the engineaxis 70 (as shown at successively later points in time in FIGS. 1-4) theouter surface 76 thereof will always abut the cusps 75 on the stator. Itwill be noted from FIGS. l-4 that although the orientation of eachtangent of the rotor surface at its point of contact with a stator cusp(e.g., a tangent line 111) varies cyclically as shown as the rotor 10goes through one cycle of rotation, the above-described oscillationmovement of the stator will cause a correspondingly oriented portion ofthe associated stator cusp (e.g., the cusp 750) to engage the rotorsurface at all times and therefore assure nonbinding operation.

This rotor-cusp arrangement divides the working space inside the statorwall 32 into three combustion chambers 71, 72, and 73. These chambersare angularly bounded by adjacent pairs of the cusps 75 and radiallybounded by the stator wall periphery 32a and the outer surface 76 of therotor 10. Each of the chambers 71, 72, and 73 will vary cyclically involume as the rotor 10 revolves about the axis 70. For example, theupper chamber 71 is shown at approximately its minimum volume positionin FIG. 1. As the rotor 10 revolves clockwise, the volume of the chamber71 increases and reaches its maximum when the rotor is in the positionshown in FIG. 3. Further rotation of the rotor, as depicted in FIG. 4,will decrease the volume of the chamber 71 until the rotor again reachesthe position shown in FIG. 1, at which time the cycle starts again.

Corresponding volume changes of the chambers 72 and 73 are identical inamplitude to that of the chamber 71, but are out of phase therewith;that is, the chamber 73 reaches its minimum volume position when therotor is in the position shown in FIG. 2, i.e., sometime after thechamber 71 reaches its minimum position.

The chamber 72 reaches its minimum volume position in the position shownin FIG. 4, i.e., at a point of time later than that of the chamber 73.It will be noted that the overlapping volume changes in the severalchambers 71-73 are similar to those experienced in the operation of thecylindrical chambers in a reciprocating piston engine having overlappingpower strokes.

In order to operate the engine 69 as a four-cycle internal combustionengine having three working chambers with overlapping power strokes,each of the chambers 7173 are fitted with a spark plug 33 extendingthrough the stator wall 32 at a position intermediate thechamberbounding cusps 75. The rotor 10 is provided with a first radialchannel 11 that communicates with a suitable carburetor in the mannerdescribed below for supplying an ignitable fuel mixture into thethen-opposed one of the chambers 71-73. The rotor is further providedwith a second radial channel 12 angularly spaced from the channel 11 forscavenging the exhaust from another one of the chambers 71-73. I

As shown pictorially in FIG. 1, an ignitable charge is being supplied bythe rotor channel 11 to the chamber 72, Whll e tl'l6 channel 12 isscavenging exhaust from the charfiber 73. The chamber 71, which is atits minimum volume position, is being ignited by a spark from the plug33, which, is energized from a suitable distributor (not shown).Expansion of the chamber 71 because of the ignition of the compressedcharge, which expansion takes place at the point in time depicted inFIG. 2, imparts rotary motion to the rotor 10. scavenging of theexpanded charge in the chamber 71 by the rotor channel 12 in preparationfor the receipt and compression of the next charge therein is shown inFIGS. 3-4.

Similar four-stroke operations or the chambers 72 and 73 are shown inFIGS. 1-4, with the ignition strokes of the chambers 73 and 72 occurringsuccessively later than the ignition strokes in the chamber 71.

The rotation of the rotor 10 in the clockwise direction as a result ofthe combustion chamber expansions fol lowing each of the ignitionstrokes in the chambers 71-73 is accomplished with essentially nointermittent impact loading of the fluid-tight packing (not shown) thatseals each junction between a cusp 75 and the outer rotor surface 76.The resultant force applied to the packing from the oscillatingmovements of the cusps 75 and the rotary movement of the epicyclic rotor10 will tend to maintain a constant pressure on the packings as therotor 10 rotates. Therefore, the impact loading and fatigue problemscharacterizing prior art rotary engines of the intermittenb contact typedescribed above are greatly minimized. Moreover, it will be noted fromFIGS. 1-4 that since (1) the working chambers of the engine are alwaysangularly bounded by an adjacent pair of the stator cusps and (2) theoscillating stator (and therefore the cusps) experience no net angulardisplacement, each chamber will occupy an essentially fixed angularsector around the engine axis, so that problems of ignition and ofsupply and scavenging of the ignitable fluid are minimized.

FIGS. 5-7 illustrate, in more structural detail, a rotary engine whosecombustion portion functions as described above in connection with FIGS.1-4. As shown best in FIG. 7, the rotor is afiixed, as by a plurality ofbolts 57-57 (one of which is shown) to a pair of flanges 7A- 7A on amain engine shaft 7 for rotation about the engine axis 70. The shaft 7is supported for rotation on both sides of thet rotor 10 by a pair ofbearings 9-9 suitably carried in a housing 58. The central gear 6 isaffixed to the shaft 7 at a location axially remote from the rotor 10.

An ignitable mixture is supplied from a carburetor 17 to the radialchannel 11 of the rotor 10 via a hollow inlet passage 80 supportedcoaxially within the shaft 7 by a plurality of ribs 81-81 (FIG. 5).Similarly, exhaust gases entering the radial channel 12 (FIG. 7) arevented by means of (1) an outlet passage 82 isolated from the inletpassage '80 by a rotor bifurcation 83, and (2) a centrifugal wheel 4communicating with the passage 82 and mounted on the shaft 7.

As shown in FIG. 5, which corresponds to the instancous rotor positionshown in FIG. 3, a head packing 42 forming a seal between the rotorsurface 76 and the cusp 75A is depicted. The packing 42 is held in placeby a retainer 39. A pair of corner packings 38-38 (FIG. 8) are disposedon either side of the head packing 42. As shown in FIGS. 12-13, eachcorner packing 38 is supported between the retainer 39 and a side wall31 of the stator by means of a plurality of blade springs 43-43. Theside wall 31 is joined to the peripheral wall 32' (FIG. 6) of the statorby means of a plurality of bolts 5252, one of which is shown.

Each corner packing 38 (FIG. 8) is joined, via an elastic ring 45, to apair of side packings 46-46, which may be supported on each statorsidewall via a blade spring (not shown).

The packings 38 and 46 provide a fluid-tight seal between each side wall31 (FIG. 6) of the stator and the stator and the adjacent one of a pairof opposed sidewalls 77-77 (FIG. 7) of the rotor 10.

Alternate forms of side packings are shown in FIGS. 9-11. In thearrangement shown in FIG. 10, the side packings include a plurality ofcircumferential segments 47-47 received in a ciroumferentially groovedmember 62, which may be affixed to or form part of the sidewall 31. InFIG. 11, the side packing is shown as a circumferential packing rim 63,which may be lubricated via a passage 50. In each of these two cases,the side packing is held in place by a blade spring 49.

To assure static and dynamic balance of the stator, a counterweight(FIG. 5) is aflixed to each of the planetary gears 21 in a positiondiametrically opposed to the offset position of the stator projection 23received therein.

The sidewalls 77 of the rotor 10 are provided with a plurality of ribs8-8 for purposes of air cooling. Similarly, each stator sidewall 31 isprovided with a plurality of ribs 34-34 and the outer surface of thestator peripheral wall 32 (FIG. 6) carries a plurality ofcircumferential cooling ribs 35-35.

The stator projections 23 are affixed, as by a plurality of bolts 41(one of which is shown) to the sidewall 31 of the stator. Angularadjustment of the point of receipt of the projection 23 in theassociated planetary gear 21 is facilitated by means of an eccentricsleeve 26 carried in the projection 23 and in the sidewall 31.

Each planetary gear 21 is supported for rotation on its axis 74 by meansof a pair of bearings 18 and 19. Lubrication of the bearings 18 and 19,the mated gears 6 and 21, the engine packings 38, 42, and 46 (FIG. 8),the projections 23 (FIG. 6) and the engine shaft bearing 9 isaccomplished by oil suitably pumped from a crankcase 30 to a channel 59.The latter channel distributes the oil to the various elements to belubricated via suitable passages e.g. 22, 24, and 25. The oil is thencollected in an oil sump 29 and routed back to the crankcase 30. A pairof bafile plates 27 and 28 are provided for restricting the oil pathfrom the sidewall 31 of the stator.

As shown best in FIG. 7, the rotor 10 is air cooled by means of aplurality of running blades 15A which direct the air around the rotorcooling ribs 8 and radial ribs 8A via a plurality of passages 14 in theengine shaft 7. The air is removed from the rotor through the passages14 and a fan 5 mounted on the shaft 7.

The centrifugal wheel 4 is cooled in two ways: 1) by the fan 5 and (2)through air vented fom the interior of an output shaft 1 through anaxial passage 3 and a radial passage 2.

The stator is cooled by means of a fan 13 mounted on the engine shaft 7.The fan 13 directs air through the channels 36 (FIG. 6) to cool thestator ribs 34 and 35 in the respective areas of the three spark plugs33. The air leaves the stator through a plurality of apertures 37-37(FIG. 5).

If desired, the rotor 10 may be adapted for gasoline injection or Dieselapplications in the manner shown in FIG. 14. This may be accomplished bypassing fuel from an axial conduit 56 associated with a suitable source(not shown) to a radial nozzle 53 in the rotor 10. The fuel flow paththrough the rotor 10 includes a radial passage 54 terminated by thenozzle 53, and an axial passage 81 communicating at opposite ends withthe conduit 56 and the radial passage 54.

What is claimed is:

1. In a rotary engine having a shaft rotatable around a first fixedaxis:

a first gear mounted on the shaft for rotation therewith;

N second gears in external engagement with the first gear at equalangular intervals around the first axis, each of the second gears beingsupported for nonorbital rotation about individual second fixed axesdisposed parallel to the first axis;

a hollow stator having an inner peripheral surface including N inwardlyprojecting cusps spaced at equal angular intervals around the innerperipheral surface;

a plurality of projections individually interconnecting like off-axispoints on the second gears to corresponding points on the cusps of thestator to support the stator for oscillation about the first axis alongan epicyclic path during each cycle of rotation of the second gears toprovide a zero net angular displacement of the stator during each suchcycle; and

a rotor mounted on the shaft for rotation therewith within the stator,the rotor having an epicyclic outer peripheral surface in continuousengagement with each of the cusps of the oscillating stator to define Nworking chambers, each chamber being bounded angularly by an adjacentpair of the cusps, whereby each chamber occupies a fixed mean angularsector of 360/N around the first axis.

2. An engine as defined in claim 1, further comprising a counterweightaffixed to each of the second gears at 7 a location diametricallyopposite to the associated olfaxis point.

3. An engine as defined in claim 1, further comprising in combinationfirst and second pairs of side walls respectively joined to andenclosing the outer epicyclic surface of the rotor and the peripheralwall of the stator respectively, each of the first and second wallshaving a plurality of cooling fins thereon; and means directing air overthe cooling fins in the first and seconds walls.

4. An engine as defined in claim 1, further comprising a plurality offirst packings individually associated with each cusp, and meanssupporting each first packing within the associated cusp for engagementwith the outer epicyclic surface of the rotor.

5. An engine as defined in claim 4, further comprising a plurality ofsecond packings supportable on the side walls of the stator andcooperable with the first packings to provide fluid-tight seals for eachchamber.

6. An engine as defined in claim 1, in which the engine shaft is hollow,and the rotor is provided with a pair of radial channels spaced alongthe outer surface of the rotor and extending inwardly from the outersurface to communicate with spaced portions of the interior of theengine shaft.

7. An engine as defined in claim 6, further comprising centrifugal meansmounted on the engine shaft and communicating with one of the radialchannels of the rotor through the interior of the engine shaft.

References Cited UNITED STATES PATENTS 914,627 3/ 1909 Alcorn. 3,244,1554/ 1966 Laudet. 3,280,802 10/1966 Froede 230145 3,348,529 10/1967 Assum230145 3,359,951 12/1967 Sabet 230--145 3,306,531 2/ 1967 Oppermann.3,291,063 12/1966 Jacobs 103132 3,364,907 1/ 1968 Jeanson.

MARK M. NEWMAN, Primary Examiner A. D. HERRMANN, Assistant Examiner US.Cl. X.R. 418-160, 130

